The objective of this research is to advance the technology used for noninvasive, simultaneous measurement of signals related to neural currents and hemodynamics in the human brain. Diffuse optical tomography (DOT) is an imaging extension of near-infrared spectroscopy (NIRS) that is used to measure cerebral blood oxygenation changes with high temporal resolution. DOT is compatible with electroencephalography (EEG) and magnetoencephalography (MEG), which respectively measure electrical potential and magnetic fields from neural currents. Combining DOT with EEG and MEG provides a window into the temporal relationship between neural and vascular dynamics in the brain. Improved spatial localization for neurovascular studies can be achieved by combining DOT and EEG with functional magnetic resonance imaging (fMRI). Studies of the neurovascular relationship will bring scientific breakthroughs in our understanding of human brain physiology and in the diagnosis and monitoring of patients with neurological diseases. These studies, however, require newly engineered probes for simultaneous measurement from the human head with multiple measurement modalities. The thrust of this work is to redesign the DOT probes to achieve geometric conformity and materials compatibility with EEG, MEG and MRI. This research has two aims. First is to address the design and fabrication of a multimodal DOT probe. The key specifications are to optimize the tomographic resolution and spectroscopic accuracy with a new probe while maintaining compatibility with EEG, MEG and MRI. The second aim is to test the performance of the new probe. The test procedure will include measuring contact forces under each sensor on a variety of head shapes and quantifying the motion artifacts induced by moving a physical head model with a linear stage. Evaluations will also be run on healthy human volunteers for the set- up time, subject comfort and signal-to-noise ratio under separate and multimodal conditions. Local research and clinical scientists involved in neuroimaging will be invited to offer critical review of the probes. Future applications of a multimodal DOT probe include improving diagnosis and treatment monitoring based on a neurovascular biomarker made possible by this research. New technologies for neurological assessment are vital as the prevalence of age-associated neurological disease increases in the United States. PUBLIC HEALTH RELEVANCE: This research will produce a new noninvasive probe for concurrent measurement of neural and vascular signals related to human brain function. This new tool is needed to support neuroimaging research that aims to advance our understanding of the relationship between neural activity and cerebral blood flow changes. Research on the neurovascular relationship will ultimately have long-term benefits to understanding the aging brain and diagnosing neurological diseases.